1) Field of the Invention
This invention pertains to the field of optical modules, and more particularly, a method for fabricating an optical module by fixedly attaching an optical fiber to a platform such that the input aperture of the optical fiber remains in alignment with a light output of a light source (e.g., a laser diode) after attachment.
2) Description of the Related Art
FIG. 1 shows an exemplary optical module 100. The optical module 100 is a so-called xe2x80x9cbutterfly module,xe2x80x9d so named because it has a plurality of electrical leads 105 (e.g., seven) extending from first and second sides 102, 104 on opposite sides of the optical module 100, and an output optical fiber 110 extending from a third side 106 generally perpendicular to the first and second sides 102, 104. The optical module 100 also includes platform 120 on which is mounted a light source (e.g., a laser diode 130) which outputs and supplies light to an input aperture 112 of the optical fiber 110.
A critical characteristic of the optical module 100 is the alignment of the light output of the laser diode 130 and the input aperture 112 of the optical fiber 110. Especially in the case of a single mode fiber, it is critically important that the light output of the laser diode 130 be precisely aligned with the input aperture 112 of the optical fiber 110. However, in the prior art, after the laser diode 130 and the optical fiber 110 are precisely aligned, they are subject to significant misalignment during the process of attaching the optical fiber 110 (and/or the laser diode 130) to the platform 120 of the optical module 110.
Accordingly, it would be advantageous to provide an improved method of fabricating an optical module. In particular, it would be advantageous to provide such a method including an improved method of fixedly attaching an optical fiber to a platform of the optical module such that the optical fiber and a light source remain precisely aligned even after they are both attached to the platform. Other and further objects and advantages will appear hereinafter.
The present invention comprises a method for fabricating an optical module, including a method of fixedly attaching an optical fiber to a platform of the optical module such that the input aperture of the optical fiber remains in alignment with a light output of a light source (e.g., a laser diode) after attachment.
In one aspect of the invention, a method is provided for fabricating an optical module including a laser diode producing light, an optical fiber having an input aperture aligned to receive the light, a ferrule fit around an exterior of the optical fiber, and a platform. A weld clip is provided having a pair of vertical walls each connected to a corresponding base wall formed at an angle of less than 90 degrees with respect to the corresponding vertical wall. The weld clip is inserted over the ferrule so that there is no gap between the ferrule and the vertical walls of the weld clip. The optical fiber is initially aligned to the laser diode to substantially optimize (e.g., to substantially maximize) coupling of light into the input aperture of the optical fiber. Next, the weld clip is fixedly attached to the platform via the base walls, creating a gap between the optical fiber and the vertical walls of the weld clip. Subsequently, the optical fiber is realigned to the laser diode to substantially optimize coupling of light into the input aperture of the optical fiber. Finally, the weld clip is fixedly attached to the ferrule.
In another aspect of the invention, a method is provided for fabricating an optical module including a light source producing light, an optical fiber having an input aperture aligned to receive the light, a ferrule fit around an exterior of the optical fiber, and a platform. The method comprises inserting a weld clip over the ferrule so that there is no gap between the ferrule and the weld clip, initially aligning the optical fiber to the light source to substantially optimize coupling of light into the input aperture, attaching the weld clip to the platform, realigning the optical fiber to the light source to substantially optimize coupling of light into the input aperture; and attaching the weld clip to the ferrule.